Adding lights to loft

[HarryPaget]

Hello, Experts,

I'm about to add two new fluorescent tube lights to my pop's loft by fitting a JB to the upstairs lighting ring.

I've checked the very useful wiring diagrams section and am fairly sure I've got this right, but the existing electrics are red/black and the new cabling will be brown/blue (1.5mm t&e), so I just wanted to make sure that:

a) it's O.K. to add 'new' to 'old', and

b) my wiring diagram is correct (see attached)

Any help/advice much appreciated.

Harry

Untitled

• HarryPaget
• 6 Sep 2014
• 1

[/img]

 

[RF Lighting]

Looks ok. Make sure you are really connecting to a supply cable. Not every red / black cable will be a supply.

Also if there is an existing junction, it would be best to take your feed from it rather than adding another.

 

[HarryPaget]

Thanks, RF Lighting,

The supply cable I'm hoping to use is the one that drops through the roof floor to feed all the ceiling roses in the upstairs rooms; it doesn't appear to have any other junction boxes fitted but, out of interest, is there a reason (other than cosmetic tidiness) that taking the feed from an existing box is preferable to adding a new one?

Thanks again,

Harry

 

[sparkwright]

Can't see any real reason for taking the feed from an existing junction box. If there is an existing junction box, it's likely to have lots of wires in it anyway, so you would have to run one cable from that a new junction box.

You may be able to get your supply from an existing ceiling rose, if it contains a permanent live and neutral and earth.

You don't necessarily need a junction box if you run your new supply cable to the switch, then run cable from the switch to the new lights. This way you connect the neutrals together in a connector block, and run the lives through the switch.

No reason you can't use a junction box though, just keep it in a reasonably accessible place.

 

[JohnW2]

... out of interest, is there a reason (other than cosmetic tidiness) that taking the feed from an existing box is preferable to adding a new one?

It's pretty marginal, but every junction box (indeed, any connection to a cable) represents a potential 'point of failure' (terminal screws have been known, by one process or another, to 'work loose' over time) - so unnecessarily adding additional potential 'points of failure' is theoretically not ideal. Just think of ('unnecessarily') chopping your garden hose into several pieces and then re-joining them with hose connectors - you will have increased the chances of one of those connections eventually 'flying apart' and spraying you with water!

Kind Regards, John

 

[HarryPaget]

Thanks sparkwright,

The loft-space is about to be re-insulated (up the recommended 10" thick rock-wool) and boarded across the central two-thirds (leaving the less useful space towards the eaves unboarded), so I'd planned to install the JB at a point not covered by the new floor, for ease of access.

Thanks for your help – all very useful.

Harry

 

[HarryPaget]

Thanks, JohnW2,

Sound logic; makes sense!

Thanks for your time,

Harry